The present invention relates to a power semiconductor device.
A power semiconductor device for controlling and converting a high voltage and a large current has been recently widely used in the power electronics field including power, transportation, and home electric appliances and it is requested to further improve the performance of the device and further decrease the size of the device. Therefore, research and development have been positively performed in order to meet the above requests.
FIGS. 7 and 8 are a top view and a sectional view respectively, showing the internal structure of a conventional power semiconductor device. In case of the power semiconductor device 40, a plurality of circuit patterns 43, 44, and 45 are formed on the upper faces of insulating substrates 41 and 42 and moreover, a plurality of power semiconductor devices 46 are mounted on the upper face of the circuit pattern 44. Wires 47 and 48 are connected between the electrode of each semiconductor element 46 and the circuit pattern 43 and between the circuit patterns 44 and 45.
Moreover, the power semiconductor device 40 has electrode terminals 50 and 51 insert-formed in a case 49 as external-connection terminals and these terminals 50 and 51 are connected to the circuit patterns 43 and 45 through wires 52 and 53 respectively.
As shown in FIG. 8, the lower end of the case 49 is bonded to the circumference of a metallic base 54 on whose upper face the insulating substrates 41 and 42 are provided. Though not illustrated, resin is injected into the case 49 to seal each component in the case 49. In case of the power semiconductor device 40, the current applied to the electrode terminal 50 is supplied to the semiconductor element 46 via the wire 52, the circuit pattern 43 on the insulating substrate 41, and the wire 47, controlled by the semiconductor element 46, and then moreover supplied to the electrode terminal 51 via the circuit pattern 44, wire 48, circuit pattern 45, and wire 53.
However, to supply a large current to the circuit patterns 43 and 45 formed on the insulating substrates 41 and 42 of the conventional power semiconductor device 40 having the above structure, there are problems that it is necessary to increase the widths of the circuit patterns 43 and 45 and thereby, the device increases in width. Moreover, because bonding wires 52 and 53 are connected between the electrode terminal 50 and circuit pattern 43, and between the electrode terminal 51 and circuit pattern 45 respectively, there are problems that many wires are necessary and the time required for wire-bonding increases in order to supply a large current between them.
It is therefore an object of the present invention to provide a power semiconductor device to which a large current can be applied and which can be compactly and more simply fabricated.